In this article, we'll dive deep into the workings and advantages of BufferedReader.
1. Introduction
BufferedReader is a part of the java.io package. It reads text from a character-input stream, buffering characters to provide efficient reading of characters, arrays, and lines.
2. Why Use BufferedReader?
Efficiency: Instead of reading one character at a time, BufferedReader reads a larger block (buffer) at once, minimizing I/O operations, which enhances performance.
Convenience: The readLine() method allows easy reading of a string line.
3. Constructing a BufferedReader
The most common practice is to wrap a BufferedReader around a FileReader:
FileReader fr = new FileReader("sample.txt");
BufferedReader br = new BufferedReader(fr);
4. Essential Methods
Some key functions of BufferedReader include:
read(): Reads a single character.
read(char[] cbuf, int off, int len): Reads characters into a portion of an array.
readLine(): Reads a line of text.
close(): Closes the reader and releases system resources.
5. A Simple BufferedReader Example
Let's glance at a basic example:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class BufferedReaderDemo {
public static void main(String[] args) {
String fileName = "sample.txt";
try (BufferedReader br = new BufferedReader(new FileReader(fileName))) {
String line;
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
6. Pairing with InputStreamReader
While it's standard to use BufferedReader with FileReader, it can also wrap around InputStreamReader for reading from other input sources like console input:
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String input = br.readLine();
7. Things to Remember
Closing Stream: Always ensure you close the BufferedReader after using it. A try-with-resources block, as shown in the example, is a recommended way to handle this.
Exception Handling: Handle potential IOExceptions when working with BufferedReader.
8. When to Use BufferedReader?
Efficient Text Reading: Utilize BufferedReader when reading large text files or streams. Its internal buffering mechanism greatly improves reading efficiency by reducing the number of I/O operations, as it fetches chunks of characters rather than reading one character at a time.
Read Lines Conveniently: BufferedReader offers the readLine() method, which simplifies reading files line by line. This is particularly helpful when parsing structured text files like CSVs or reading configuration files.
Wrapping Other Readers: BufferedReader can wrap around other character-based readers, such as FileReader or InputStreamReader, to augment them with buffering capabilities. This layering approach provides both the data source and the efficient buffered reading capability.
Related Java I/O Classes
- FileOutputStream Class in Java
- FileInputStream class in Java
- ByteArrayOutputStream Class in Java
- ByteArrayInputStream Class in Java
- DataOutStream Class in Java
- DataInputStream Class in Java
- ObjectOutputStream Class in Java
- ObjectInputStream Class in Java
- BufferedOutputStream Class in Java
- BufferedInputStream Class in Java
- BufferedWriter Class in Java
- BufferedReader Class in Java
- FileWriter Class in Java
- FileReader Class in Java
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